Comparison of adaptive statistical iterative and filtered back projection reconstruction techniques in quantifying coronary calcium

• We investigated changes in coronary calcium scoring with the use of ASIR.
• Agatston score and calcium volume decreased with ASIR compared to FBP.
• Severity classification based on Agatston score changes when ASIR exceeds 50%.
• Compared to FBP, ASIR might decrease maximum CT values and pixel numbers ≥130 HU.

BackgroundAdaptive statistical iterative reconstruction (ASIR) has been used to reduce radiation dose in cardiac computed tomography. However, change of image parameters by ASIR as compared to filtered back projection (FBP) may influence quantification of coronary calcium.ObjectiveTo investigate the influence of ASIR on calcium quantification in comparison to FBP.MethodsIn 352 patients, CT images were reconstructed using FBP alone, FBP combined with ASIR 30%, 50%, 70%, and ASIR 100% based on the same raw data. Image noise, plaque density, Agatston scores and calcium volumes were compared among the techniques.ResultsImage noise, Agatston score, and calcium volume decreased significantly with ASIR compared to FBP (each P < 0.001). Use of ASIR reduced Agatston score by 10.5% to 31.0%. In calcified plaques both of patients and a phantom, ASIR decreased maximum CT values and calcified plaque size.ConclusionIn comparison to FBP, adaptive statistical iterative reconstruction (ASIR) may significantly decrease Agatston scores and calcium volumes.